Sound amplifier



Dec. 2, 1930.

C. C. FLYNN SOUND AMPLIFIER Filed March 19, 1928 INVENTOR. Ccwles C,Fynn.

` n ATTORNEY.

Patented Dec. 2, 1930 CHARLES C. FLYNN, OF DETROIT, MICHIGAN SOUNDAMPLIFIER Application filed March 19, 1928. Serial No. 262,616.

My invention relates to a new and useful improvement in a soundamplifier or sounding chamber intended for various uses where a soundamplifying device is required, such as sound chambers of phonographs,loud speakers on radios, etc.

.It is an object of the present invention to provide sound amplifyingdevice of this kind in which reflecting surfaces of the device arearranged and curved to provide surfaces determining harmonic curves, tothe end that thev natural oscillations in the sound waves may not beinterfered With, but may be increased and amplified to produce thedesired amplification in the device.

It is another object of the invention to provide a device of this kindwhich will be simple in structure, economical of manufacture and highlyeiiicient in use.

Another object of the invention is the provision of passages throughwhich the sound must pass-before emanating from the amplifying deviceand forming these passages With surfaces designed to amplify the soundspassing therethrough.

Other objects will appear hereinafter.

The invention consists in the combination and arrangement of partshereinafter described and claimed.

The invention will be best understood from a reference to theaccompanying drawings which `form a part of this specification and inwhich,

Fig. 1 is a longitudinal central sectional view of the invention.

Fig. 2 is a sectional view taken on line 2 2 of Fig. i.

Fig. 3 is a sectional view taken on line 3 3 of Fig. 1.

Fig. 4 is a fragmentary sectional view taken on line 4-i of Fig. 3.

The device as set out herein has proven from experience to be mostefficient in amplifying and it has been attempted to construct thedevice along certain well defined mathematical lines based on theconception that sound is in the form of wave motion and that thevibrations or oscillations are in line with the direction of propagationof the sound, and

that these vibrations Vor oscillations are inV reality the result of theimpact of the particles or molecules of the medium of propagation due tothe elasticity of these particles. It is believed that the motion from astate of rest or a change in direction, or change in frequencyofoscillations along the direction of propagation, is due to theapplication of'a force or forces to the molecular structure of themedium of propagation, this molecular impact transmitting motion orvibration from the initial point of application to the ultimate end, themedium itself not being moved bodily but transmitting the motion frommolecule to molecule.

To increase these oscillations or vibrations by reflection or refractionby the addition of resultant reflected or refracted oscillations alongthe axis of motion, is one of the objects of the invention, and this isaccomplished by determining the profile of the various curves in thesound passages, so that these curves are harmonic in nature.

In the sound passages two sides are designed to be parallel and twosides curved, the curve being a harmonic one, and the curved sidesterminating in parallel sides at the same point that the parallel sidesbegin to curve.

Ahead 7 which is designed for attachment to the conduit which leads fromthe sound producer, is attached by suitable screws 8 to thepassage-forming walls 9 and 1() and the Wedges 13 and 14. The innersurface of these walls 9 and 10 are parallel for a portion of theirdistance as at 11, and are flaring outwardly at the portion 12, thiscurve being a harmonic one.

The inner surface of the wedge members 13 and 14 are inclined and theirinclination terminates at the point where the surface 12 begins to curveoutwardly.

The housing comprises side walls 15 and 16 which are made preferably ofresonant material, such as wood, and secured to the inner, surface ofeach of these walls at the central portion thereof are the securingplates 17 and 18 which are formed preferably heartshaped, as appears inFig. 1.

Hollow units are provided for positioning atopposite sides of themembers 9 and 10,

as shown clearly in Figs. 1 and 2, these units comprising the side walls19 and 20, which engage against the inner surfaces of the securingplates 18 and 17.

Connecting these side walls 19 and 20 is the transversely extended wall21 which is adapted to engage against the sides of the members 9 and 10,so that sound passing inwardly betweenthese members .9 and is notpermitted to escape except around the ends of Athese members, the endsof these members being curved, as clearly appears in Fig. 3. f

Engaging the outer edges of the side walls 19 and 20 and the upper andlower edges of the wall 21, so as to enclose this unit and form a closedhollow unit, is a diaphragm or closure 22 preferably made from paper orother similar material.

A similar unit is mounted at the opposite side of the members 9 and 10and comprises the sidewalls 19 and 20', the transversely extended wall21 and the covering 22.

Engaging the outer edges of the side walls and 16 so as'tovforin withthese side walls a housing is a covering or diaphragm 23 preferably madefrom paper or the like.

Connecting the side walls 15 and 16l at' their lower edges adjacenttheir ends are the rails 24 and 25 which also serve Vas a support for asuitable closure or screen 26 which may or may not be used, as desired.

Engaging at its opposite ends the inner surface of the plates 17 and 18,adjacent their lower ends, is the refiecting plate 27 which is formed onits inner surface with recesses 28 and'29, these recesses having asurface which is curved, the curve'being a harmonic one. The surfaces ofthese recesses 28 and 29 meet at a point which is central between themembers 9 and 10.` Y

In use the sound is transmittedinto the head 7 and thence inwardly ofthe housing between the members 9 and 10, the inclined surface of thewedge members permitting a diverging of the sound waves, thesesoundwaves engaging the surface 12, passing inwardly and thence around thecurved ends of the members 9 and 10, and reflecting from the curvedsurfaces of the recesses 28 and 29,

and thence backwardly so that the surfaces 30 and 31, which are alsoVcurved slightly at a harmonic curve, will serve as a reflecting body.The sound then travels to the right or left of the device shown in overthetop of the plates 21 or 21 into the space 33V or 33.

In this regard, it will be noted that the inner vsurface of the covering23, at opposite sidesfof the transverse medial line of the main housing,is also curved at a harmonic curve and the covers 22 and 22 are alsocurved at a harmonic curve to afford the refieoting surface 34C whichcooperates with the surface 33.

lIn this way the sound, after being consageways in which the soundtravels is substantially a continuation of the passage lead- Y ingthereto, each succeeding passage increasing harmonically across twosides. In other words, each succeeding passage has a cross section widthsuch that it increases harmonicaly ly from the start of the firstsection before the sound reaches the recesses 28 and 2,9 and continuesuntil the sound is transmitted from the chambers 33 and 33. The twofinal openings which are the ends of the chambers 3,3. and 33 areprovided with a view to produc` Y ing the sensation of depth or spacenot obtainable by a single horn or device.

in this ainplifyingrdevice there are pro# Yvided a pair'of cooperatingsound transmitters or amplifiers, receiving the sounds from the samesource, and constructed on their inner or reflecting surfaceharmonically.

While I have illustrated and describedV the preferred form of myinvention, I do not-V Y wish to limit myself to the precise details ofstructure shown, but desire to avail myself of such variations andmodifications as come within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire tosecure by Let-tersV Patent is: Y

1. A device of the class described, com' prising: a housing; a pair ofpassage forming oppositely disposed walls spaced apart; a pair 'ofoppositelyV disposed wedges co-operating with said walls andfenclosing apassage, the inner surfaces of said wedges being inclined to theirlongitudinal axis, the inner surfaces of said wall formingmembersthroughout the major portion of said wedges being parallel andthroughout the rest of their length being fiared outwardly from eachother on harmonic curves.

2. A device of the class described, comprising: a housing; a pair ofpassage forining oppositely disposed walls spaced apart; a pair ofoppositely disposed wedges co-operating with said walls and enclosing a,pas-

sage, the inner surfaces of said wedges be ing inclined to theirlongitudinal axis, theinner surfaces of said walll forming members.throughout the major portion of said wedges being parallel andthroughout the rest of their length being fiared outwardly from eachother on harmonic curves; areflecting plate positioned vadjacent theends of said wall forming members in spaced relation thereto andextended across the passage formed thereby and provided at oppositesides of the longitudinal medial line of said passage with curvedrecesses, the curve of said recesses being harmonic.

3. A device of the class described, cornprising: a housing having sidewalls in spaced relation; a covering engaging the edges of said sidewalls on all sides except one and enclosing the space between said sidewalls; securing plates mounted on the inner surface of said side walls;a reflecting plate joining said securing plates adjacent the open sideof said housing; a pair of hollow members projecting inwardly of saidhousing and engaging adjacent their outer ends the sides of saidreflecting plate; and passage forming members projected through one sideof said housing and extending inwardly between said hollow members andforming a sound passage between the same terminating adjacent saidrefiecting plate.

l. A. device of the class described, comprising: a housing having sidewalls in spaced relation; a covering engaging the edges of said sidewalls on all sides except one and enclosing the space between said sidewalls; securing plates mounted on the inner surface of said side walls;a reflecting plate joining' said securing' plates adjacent the open sideof said housing; a pair of hollow members projecting inwardly of saidhousing and engaging adjacent their outer ends the sides of saidreflecting plate; and passage forming members projected through one sideof said housing and extending inwardly between said hollow members andforming a sound passage between the same terminating adjacent saidreflecting plate, said reflecting plate having at opposite sides of themedial line of said passage grooved recesses formed therein.

In testimony whereof I have signed the foregoingl specification.

CHARLES C. FLYN N.

